Accomodate for Ganache negative transaction cost during debug_traceTransaction

[argonavist]

As per trufflesuite/ganache#277 and trufflesuite/ganache#578 a Ganache blockchain may report negative gas cost for a REVERT or RETURN EVM command.

The StructLog struct (module/debug/trace.go) for the result of the debug_traceTransaction RPC is using a uint to save the gas resulting in an error.

[lmittmann]

The RPC-methods supported by this package are meant to support go-ethereum which can not report negative gas costs. Unfortunately the more advanced RPC-methods like tracing differ a lot between nodes and testing frameworks in their output format.

You can do two things:

1. implement a custom debug_traceTransaction for Ganach. w3 is extendable with custom method bindings. You need to implement the w3types.Caller interface. See e.g. https://github.com/lmittmann/w3/blob/v0.13.0/module/eth/call.go#L98 as reference.
2. play with the w3vm branch which will bring something like Ganache, but pure Go and super fast with state forking via RPC to w3. It allows tracing using any vm.EVMLogger implementation. However, this is still experimental and only "documented" here: https://pkg.go.dev/github.com/lmittmann/[email protected]/w3vm

[argonavist]

Thank you very much for your very detailed reply.
That w3vm branch looks great and so does the ease in extending through w3types.Caller.